Apparatus for manufacturing thin rubber articles



' March 30, 1943. R. E. THOMPSON APPARATUS FOR MANUFACTURING THIN RUBBER ARTICLES Filed April 9, 1940 INVENTOR Way .5 7i any 05022 ATTORNEYJ Patented Mar. 30, 1943 APPARATUS FOR MANUFACTURING THIN RUBBER ARTICLES Roy E. Thompson, Nyack, N. Y., assignor to Lorica Laboratories Inc., Jersey City, N. 1., a corporation of New Jersey Application April 9, 1940, Serial No. azassa 2 Claims.

This invention relates to thin rubber, or hollow elastic, articles and has for its object certain new and useful improvements in apparatus for manufacturing such articles. The invention relates more particularly to improvements in the art of making sanitary elastic sheaths by the clipping process, the sheaths being formed by a sheath proper and a band integrally attached thereto at its opening. In accordance with these improvements, elastic bands of predetermined size and elasticity may be provided at the open ends of finger cots, thumb guards, rubber gloves, breast nipple sheaths, and other hollow elastic sheaths of a similar nature, in which the opening is substantially smaller in cross-section than the sheath itself.

In sanitary elastic sheaths of the kind contemplated, little orno reliance is placed on the sheath proper for attachment to the body. The sheath proper is merely intended to cover a part of the body. and depends essentially and primarily on its built-in elastic band for attachment to the body. The band is alone suflicient for the purpose, and this leaves the sheath free for its intended sanitary purpose. The sheath protects the part covered from contamination by outside sources; and prevents contamination of other parts by the part covered. The sheath is particularly useful in preventing loss or discharge of medication from the part covered to surrounding parts. The sheath is also useful in functioning as a cover and a support for a bandage or other cover placed over the affected part. The sheath may contain an absorbent, such as gauze, cotton, or the like, with or without medication, for treating the part affected.

It is important that the opening of the hollow elastic articles be suitably reinforced. To accomplish this result, it is the practice in some I cases to roll the elastic material at the opening into a. bead. While a round bead of this kind is satisfactory for some purposes, it is highly disadvantageous for others. For example, when the article is tightly fitted over a part of the body, such as a thumb, finger, wrist, breast nipple, etc., so as to be securely attached thereto, the rounded bead tends to dig into the flesh in an uncomfortable and painful manner. It is also difficult to control the elasticity of 9. rolled bead; the larger the bead in cross-section, the less readily it' stretches. If, therefore, the head is rolled to a size sufliciently large to inhibit painful digging into the flesh, it-will ,often lose its desired elasticity.

rounded bead may for the most part be avoided by reinforcing the opening of the hollow article with an especially added elastic band that is flat or substantially flat; and a band may be selected which will not painfully dig into the flesh and which will at the same time remain securely attached to the body. Having decided on a band of optimum width, thickness and elasticity the manufacturer may be assured that after the band is integrally attached to the hollow elastic article at its opening, the band portion of the article will have the desired characteristics.

The provision of an .elastic band integrally attached to a hollow elastic article is, however, considerably complicated when the cross-section of the band is substantially smaller than the cross-sectional area of the hollowarticle. This is especially true of elastic sheaths or bags made by the dipping process, in which the sheath has an opening very much smaller in cross-section than the sheath propen, A form, having substantially the size and shape of the article to be formed, is dipped into a suitable coating liquid. The coating remaining on the form must be removed, and therein lies the difllculty when the coating is to be integrally secured to an elastic band. As a result of my investigations, I have discovered improvements in method and apparatus which make it possible integrally to attach an elastic band of predetermined characteristicsto a thin elastic hollow article at its opening.

The invention will. be more fully understood by referring to the accompanying drawing, taken in conjunction with the following description, in

- which:

Fig. 1 is a diagrammatic representation of a shaft, showing an elastic band suitably mounted around one end thereof, useful in a practice of the invention;

Fig. 2 is a similar view, showing a head'preliminarily mounted on the shaft of Fig. 1;

Fig. 3 is a view similar to Fig. 2, but showing the head and elastic band in final position on the shaft; 7

Fig. 4 is a view similar to Fig. 3, showing the head, elastic band and shaft assembly immersed in a body of coating liquid:

Fig. 5 is a cross-sectional view on the lin 5-5 of Fig. 2;

Fig. 6 is a cross-sectional view on the line 8-6 of Fig. 4; 1

Fig. 7 is a cross-sectional view of the assembly in part showing the head, its coating and the I have found that the disadvantages of the hand as a unit separated from the shaft; and

Fig. 8 is a diagrammatic representation illustrating the removal of the elastic bag from the head.

Referring to Fig. 1, the apparatus shown comprises a shaft l0, preferably made of metal, such as aluminum, the head-end of which has a tapered section II extending from the main body of the shaft to a tapered end or tip portion II. This figure also shows an elastic band l3 suitably placed in approximate position over the tapered or head-end of the shaft. The other end ll of the shaft is threaded so as to be screwed in a base l5 and to accommodate a lock nut I6. This permits adjustment of the length of the shaft extending from the base.

Fig. 2 shows a head I! having substantially the size and shape of the finished article, in this case an elastic sheath several times larger in crosssectional area than the cross-sectional area of its opening. The head, like the shaft, is preferably made of metal, such as aluminum with a polished, smooth surface. As shown in this figure, the head is mounted over the tapered portion of the shaft Ill, and the head engages the nearest rim of the band l3.

In Fig. 3, the head is shown mounted in final position on the shaft. As the head is moved down the shaft, the head pushes the annular band down the shaft into its final position. while this occurs, the rim of the band is and remains in contact with the head.

Referring to Fig. 4, the apparatus described is shown with the free end of the shaft extending upwardly and the head-end of the shaft, at least so much of it as is covered by the head and the band, submerged in a body of suitable coating liquid l8 confined in a container IS.

The construction of the head and shaft is shown more particularly in Figs. 5 and 6. The head is provided with a shaft-opening 20 adapted to receive the head-end of the shaft. The fore portion 2| of the shaft-opening has a diameter substantially the same as that of the main body of the shaft, so that the head may be snugly fitted onto the shaft. The shaft-opening also contains a tapered portion 22 complementary to the tapered portion I I of the shaft. The bottom of the shaft-opening is a practically straight wall portion 23 adapted to receive the tapered tip portion I2 of the shaft.

The shaft is provided with an air vent passageway 24 extending from the tip of the head-end of the shaft longitudinally through the center portion of the shaft, and ending as an opening 25 in the side of the shaft at a distance sumciently removed from the final resting place of the band on the shaft so as not to be covered by coating liquid in the dipping process.

In the arrangement shown in Fig. 5, the head is preliminarily placed over the shaft and is brought in engagement with the rim of the annular band across the tapered portion H of the shaft; whereas in Fig. 6 the head and elastic band are shown mounted in final position on the shaft, with thehead and part of the band submerged in the coating liquid.

The shaft is adapted to support the elastic band at the line of juncture 26 (see Fig. 6) between the two when the head is mounted on the shaft. The shape of the head is such that a snug fit is provided between the head and shaft at the line of juncture, so that coating liquid cannot seep into the shaft opening. The head and band rim are also in close contact with one another so that coating liquid cannot penetrate to the shaft and adhere thereto. To this end,

the outer surface of the head comes substantially to a sharp line of intersection with the surface of the shaft opening in the head so that the edge 21 ,(see Fig. 8) effectively permits engagement with the rim of the band mounted on the shaft. The band may then in turn be pushed forward on the shaft while frictionally supported by the shaft.

The surface 28 of the head at and near the entrance of the shaft-opening 20 tapers away from the shaft at an angle, preferably less than 90, sufficiently small to prevent a substantial build-up of rubber at the annular line of juncture 29 between the head and the elastic band, when the assembly is dipped in a body of coating liquid. With an angle of the degree contemplated, excess coating liquid may readily drain away from the band. If there should be a substantial build-up of rubber, it would be course alter the elasticity characteristics of the band portion of the sheath.

Fig. 7 shows the head, its adhering coating and the elastic band as a unit, from which the shaft has been separated or removed. The dotted outline in the figure shows the position previously occupied by the shaft.

The apparatus may be used as follows in the practice of the invention. The annular elastic band i3, preferably of predetermined width, thickness and elasticity, is freely dropped over the tapered portions l2 and II of shaft ID. The internal diameter of the band is the same as that of the sheath when finished, and is substantially the same as the outside diameter of the shaft. When the band is dropped around the shaft in this manner, it engages the shaft frictionally and assumes what may be deemed a preliminary position.

The head H, which has the size and shape of the sheath proper, is then fitted over the tapered portions l2 and II of the shaft, as shown in Figs. 2 and 5. The head engages the nearest rim of the elastic band, and as the head is pushed down the shaft, the band is also moved along the shaft. When the head is brought in final position on the shaft, that is, when it is securely attached to the shaft, the head and band assume the position shown in Figs. 3, 4 and 6, in contact with one another. During the mounting operation, air trapped in the shaftopening 20 is vented through the passageway 21 to the outside atmosphere, in amount sufficient to prevent the building up of pressure.

With the base end of the shaft extending upwardly, the head and band are submerged in a suitable coating liquid, such as liquid rubber latex, liquid rubber, or liquid rubber cement, etc. The head is permitted to remain submerged until a thin coating of the liquid adheres to the head and the outside of the annular band.

The shaft and head are then withdrawn from the body of coating liquid, and the entire assembly is preferably placed in a drying room maintained at an appropriate temperature. If desired, and this is sometimes the preferred practice, the shaft and head assembly is subsequently returned for another dipping in the coating liquid, so that a second coating may be built onto the first coating; after which the shaft and head assembly is again returned to the drying room. This procedure may of course be followed as often as is necessary to produce a sheath of desired properties.

After the coating on the head and elastic band has been suitably treated in this manner, the

games or v holes, by blowing them with a certain amount ofair.1

shaft is withdrawn or separated from the head..'

Due to the use of the air-vent passageway I, a vacuum is "not set up in the shaft-openingof the head to retard the separation. This may be done by grasping the head with one hand and the shaft with the other, and then pulling the two apart. Since the coating on the head is integral-' iy attached to the band, the coating and band remain with the head as the shaft is pulled through and away from the band. I

Since the band extends freely away from the head at itsopening, as shown in Fig. 7, it provides a most important-means for removing the resultant elastic sheath or bag from the head without injury to the sheath. The elastic band portion of the sheath is suitably stretched into an enlarged opening and the head is removed.

sufiiciently large to permit the expulsion of the head therethrough. This is accomplished by shoving the thumb 30 toward the fingers.

Special precautions are taken to remove stickiness from the inside and outside surfaces of the sheath. To this end, the head, coating and band assembly, as shown in Fig. '7 withshaft removed, is dropped into a bodyof suitable powder, such as talcum or other appropriate material well-- known .to the art. The powder promptly removes the stickiness fromthe outside surface of the coating. The operator then grasps the assembly, as shown in Fig. 8, and expels the head Iclaim:

1. In apparatus for the manufacture of elastic bags by the dipping process, the bag being formed of a bag proper and a" band integrally attached thereto at its opening, the opening being substantially smaller incross-section than the interior of; the bag when both are unextended, the combination comprising'a shaft having a diameter substantially as large as. the opening of the a f bag, the shaft being .adapted to support an annular elastic'band, and an integral head having 1 a continuous outersurface-substantially the size and shape of the bag proper, the head having an opening of a. size adapted to receive one end of the shaft with a snug'flt. whereby the head may be removably mounted on said end of the shaft and freely suspended from and supported by the shaft during a dipping operation. and said head .being provided with a rounded outer surface coming substantially to a sharp annular line of intersection with the surface of the shaft when r may be used to pushjan annular elastic band along the shaft as the shaft is inserted into the the head with therim of the band mounted'on the shaft, the surface of the head at the annular head and so that the edge formed by the line of intersection will permit effective engagement of line ofjuncture with the shaft tapering away from the shaft at an angle less than 90 to preventexcessive build-up of coating material at the line of juncture when the head is dipped in a body of coating liquid and is then removed to permit draining of excess liquid.

2. Apparatus for the manufacture of elastic bags as set forth in claim 1 in which the shaft through the enlarged opening of the elastic band portion, preferably while the entire assembly is under the powder. through the enlarged opening, the sheath is turned inside out, thus assuring contact of powder with both sides of the sheath.

The sheaths are then picked out of the powder, shaken to remove excess powder and are appropriately packaged. If imperforate sheaths are desired, it is advantageous to test for pin As the head is propelled I makes a snug, sliding flt with the opening in the head and the end thereof which is adapted to be inserted-into the opening in the head is tapered so that it is adapted to receive and temporarily to support ly placed-thereon, and in which the shaft is provided with an air vent passageway extending from the end thereof which is inserted into the head to the surface of the shaft at a distance beyond the position occupied by the head when the head is mounted on the shaft.

ROY E. THOMPSON.

the head is mounted thereon, so that the head an annular elastic band loose-- 

